Mad cow disease, or bovine spongiform encephalopathy (BSE), is a neurologic disease that affects the central nervous system of adult cattle.
It causes a spongy degeneration of the brain and spinal cord, leading to abnormal behavior, loss of coordination, and death.
BSE can be transmitted to humans who eat contaminated meat, causing a fatal condition called Creutzfeldt-Jakob disease (CJD).
There are two types of BSE: classical and atypical. Classical BSE is caused by feeding cattle with meat and bone meal of infected animals, which was banned in many countries after the outbreak in the UK in the 1980s and 1990s.
Atypical BSE occurs sporadically and randomly in older cattle, regardless of their diet or origin. It is believed to arise from a spontaneous mutation or change in the normal prion protein that is present in all mammals.
What happened in South Carolina?
On May 20, 2023, the US Department of Agriculture (USDA) announced that an atypical case of BSE was detected in a beef cow at a slaughter plant in South Carolina, as per News24.
The cow was approximately 5 years old or older and had never entered slaughter channels. The USDA said that the animal presented no risk to the food supply or to human health in the US.
This was the seventh detection of BSE in the US over the past 20 years and all but one of them have been atypical.
The first case, in 2003, was a classical BSE in a cow imported from Canada. The rest have been atypical (H or L-type) BSE, as per abc News.
The USDA said that the US has a negligible risk status for BSE and that it does not expect any trade impacts as a result of this finding.
The agency said that it conducts routine surveillance for BSE and that it works closely with international animal health organizations to protect the public and animal health.
What are the implications of this finding?
The detection of an atypical BSE case in the US is not likely to have significant consequences for the beef industry or consumers, as it is considered a rare and spontaneous event that does not indicate a widespread problem.
The US has strict measures to prevent the spread of BSE, such as banning the use of animal-derived proteins in cattle feed, removing specified risk materials (such as brains and spinal cords) from cattle over 30 months of age before processing, and testing cattle for BSE before entering the food chain.
However, some countries may impose temporary restrictions on US beef imports as a precautionary measure, as happened in the past with other countries that reported BSE cases.
For example, China suspended beef imports from Brazil for one month after an atypical BSE case was detected there earlier this year, as per Phys.org.
The US has a trade agreement with China that states that no ban can be put in place on any atypical BSE case should it occur, but the political situation between the two countries may affect their trade relations.
The detection of an atypical BSE case also highlights the need for continued vigilance and research on this disease, as there are still many unknowns about its origin, transmission, and prevention.
Scientists are working on developing better diagnostic tests, vaccines, and treatments for BSE and CJD, as well as understanding the genetic and environmental factors that influence their occurrence.